1. Field of the Invention
The present invention relates to an input key and an input apparatus for inputting input information and, more particularly, to an input key to which a plurality of input information elements are assigned, and an input apparatus provided with the input key.
2. Related Background Art
In compact, portable electronic devices (portable terminals) such as cell phones and PDAs (Personal Digital Assistants), a plurality of text information elements are generally assigned to an identical input key so as to permit a user to input the text information elements such as symbols, marks, and numbers, by a small number of input keys. Let us explain an assignment example in which the hiragana writing symbols being one of the Japanese symbol forms are assigned to input keys.
The Japanese hiragana writing symbols can be sorted into a plurality of subgroups, each subgroup consisting of five symbols. These subgroups include the “ line” group consisting of five symbols (, , , , ) respectively corresponding to five basic vowels, the “ line” group consisting of five symbols (, , , , ) respectively corresponding to the five vowels coupled with a specific consonant “K”, the “ line” group consisting of five symbols (, , , , ) respectively corresponding to the five vowels coupled with a specific consonant “S”, the “ line” group consisting of five symbols (, , , , ) respectively corresponding to the five vowels coupled with a specific consonant “T”, and so on.
For example, the five symbols of “” to “” in the “ line group” are assigned to a predetermined input key and likewise a plurality of symbols such as the “ line group”, “ line group”, “ line group”, “ line group”, . . . are assigned to other input keys for the respective line groups. Then an input symbol is selected in the order of “”, “”, “”, “”, and “” in accordance with the number of push operations of the input key for the “ line group” and likewise an input symbol is selected in the order of “”, “”, “”, “”, and “” in accordance with the number of push operations of the input key for the “ line group”.
Incidentally, in the method of selecting an input symbol in accordance with the number of push operations of the input key in this manner, the user has to consecutively push the input key five times, for example, for inputting such symbols as “”, “”, “”, “”, “”, . . . in the “ column” group, so that the input operation thereof requires labor and time and is extremely complex.
There are thus conventional technologies proposed to simplify the operation of the input key to which a plurality of text information elements are assigned. For example, a proposed technology is to support a key top of an input key in a rockable state to the four corners and to allow the user to selectively input four symbols, numbers, marks, or the like by signals of switches to be turned on according to rocking of the key top to the four corners (e.g., cf. Japanese Patent Application Laid-Open No. Heisei 11-237945). By this technology, one symbol is selected, for example, by simply pushing one of the four corners of the key top of the input key assigned four symbols, which simplifies the operation of the input key, as compared with the conventional technologies.